Fusarium ear mold (also referred to as Fusarium ear rot) is a devastating disease of maize caused by species of the Gibberella fuijkuroi complex, namely F. verticillioides, F. proliferatum, and/or F. subglutinans. It is predominantly found in the southeastern United States, southern Europe, Mexico, Brazil, Argentina, and South Africa, and affects both grain yield and quality. Fusarium ear mold can also result in contamination by several mycotoxins, including fumonisins (FUM), moniliformin (MON), and/or beauvericin, which appear to cause a number of human and animal diseases. Fumonisins, e.g., are linked to several animal toxicoses including leukoencephalomalacia (Marasas et al. (1988) Onderstepoort J. Vet. Res. 55:197-204; Wilson et al. (1990) American Association of Veterinary Laboratory Diagnosticians: Abstracts 33rd Annual Meeting, Denver, Colo., Madison, Wis., USA) and porcine pulmonary edema (Colvin et al. (1992) Mycopathologia 117:79-82). Fumonisins are also suspected carcinogens (Geary et al. (1971) Coord. Chem. Rev. 7:81; Gelderblom et al. (1991) Carcinogenesis 12:1247-1251; Gelderblom et al. (1992) Carcinogenesis 13:433-437) and have been linked to birth defects in humans (Missmer et al. (2006) Environ Health perspect 114:237-41).
The use of phenotypic selection to introgress Fusarium ear mold resistance into susceptible lines is time consuming and difficult, and since Fusarium ear mold is sensitive to environmental conditions, selection for resistance from year to year based solely on phenotype has proven unreliable. In addition, specialized disease screening sites can be costly to operate, and plants must be grown to maturity in order to classify the level of resistance or susceptibility.
Selection through the use of molecular markers associated with Fusarium ear mold resistance, however, has the advantage of permitting at least some selection based solely on the genetic composition of the progeny. Moreover, resistance to Fusarium ear mold can be determined very early on in the plant life cycle, even as early as the seed stage. The increased rate of selection that can be obtained through the use of molecular markers associated with the Fusarium ear mold resistance trait means that plant breeding for Fusarium ear mold resistance can occur more rapidly, thereby generating commercially acceptable resistant plants in a relatively short amount of time. Thus, it is desirable to provide compositions and methods for identifying and selecting maize plants with enhanced resistance to Fusarium ear mold.
Some instances of genetic resistance to Fusarium ear mold have been reported (Perez-Brito et al. (2001) Agrociencia 35:181-196; Ali et al. (2005) Genome 48:521-533; Robertson-Hoyt et al. (2006) Crop Sci. 46:1734-1743; Zhang et al. (2005) J Appl Genet 47:9-15; Robertson-Hoyt et al. (2007) Phytopathology 97:311-317; Ding et al. (2008) Mol Breeding 22:395-403).